General Concepts > s.a. lorentz group;
spacetime models; time;
[Reference
Frame].
* Interval: A useful expression is ds2 = –c2 t1t2,
where... @ Ohanian & Ruffini 94, p 70.
* Boost: A transformation
of coordinates given by t' = t cosh u +
x sinh u, x' = t sinh u + x cosh
u, for a boost along the x-axis (with tanh u =
);
The coordinates y and z in
this case are unchanged,
and the boost
vector field is
v:= x
/
t
+ t
/
x ;
In general relativity, the corresponding conserved quantity (center of energy, > see conserved quantities) for asymptotically flat spacetimes is
M(N) =
infty [N(
a qbc –
b qac)
– N,a (qbc –
fbc) + N,b (qac –
fac)] qacqbd
dSd .
* Time dilation: T =
T0;
Argue with bouncing photon clock; First tested in 1938 to within 1% of predictions
in an experiment by Herbert Ives and G R Stilwell; Verified with cosmic
ray muon decays and with GPS tests; 2007, best measurement by Gwinner et al
has accuracy quantified by a "Mansouri-Sexl parameter" of less than
8.4
10–8.
* Length contraction: L =
–1L0;
Argue based on time dilation and
L/T0 = L0/T (can
be illustrated with long car in garage); > s.a.
Lorentz-Fitzgerald Contraction.
* Velocities: Addition, u = (v1+v2)/(1+v1v2/c2) – neither
commutative nor associative due to the presence of Thomas precession; Four-velocity,
um
= dxm/d
.
* Doppler shift: Components
of vectors normal to
are
invariant, so k' perp =
kperp; for other
ones,
k' 0 =
(k0–
· k)
, k' 1
=
(k1–
k0)
;
for light
' = ![]()
(1–
cos
)
, tan
' =
sin
/[
(cos
–
)]
.
@ Transformations: Brehme AJP(62)jul
[Lorentz and Galilei, geometrical]; Lévy-Leblond AJP(76)mar,
Lévy AJP(07)jul
[derivation]; Janssen SHPMP(09) [kinematical vs dynamical explanations].
@ Length contraction: Rindler AJP(61)jun
[paradox]; Nikolic AJP(99)nov-phy/98 [accelerated
rod]; Pierce AJP(07)jul
[and lock and key paradox]; Redzic EJP(08)
[interpretations].
@ Appearance of objects: Penrose PCPS(59)
[sphere]; Terrell PR(59);
Weisskopf PT(60)sep; in
Van Bladel 84; Peres AJP(87)jun;
Blackman EJP(98)ap/97;
Field AJP(00)apr;
Morava a0804 [in
terms of groups].
@ Time dilation: Bohm & Hiley AJP(85)aug
[and active interpretation of boosts]; Saathoff et al PRL(03)
[deviations < 2.2 ×
10–7]; Gwinner MPLA(05)
[tests, rev]; Harvey & Schücking PT(05)mar
[history, and gravitational time dilation]; news pw(07)nov
[best measurement
yet].
Twin Paradox > s.a. mach's principle.
* Idea: Identical twins
who are separated, undergo different accelerations, and are then reunited will
have aged differently; Not really a paradox, it is
a kinematical special relativity effect due to differences in proper times.
@ General references: Rodrigues & Rosa FP(89),
comment Sachs FP(89);
Harpaz EJP(90);
Debs & Redhead AJP(96)apr
[and simultaneity]; Ghosal et al FPL(05)
[and equivalence principle], gq/05;
Minguzzi AJP(05)sep
[explicit formula]; Grøn EJP(06);
Kohler FPL(06)
[instantaneous turnaround as limit]; Grandou & Rubin a0704/AJP
[as
a consequence of
causality], IJTP(09) [ingredients].
@ In curved spacetime: Dray AJP(90)sep,
Barrow & Levin PRA(01)gq [closed
universe]; Bansar et al gq/05 [with
a compact dimension]; Luminet a0910-in.
@ Variations: Price & Gruber AJP(96)aug;
Cranor et al AJP(00)nov,
Wortel et al AJP(07)dec-gq [circular];
Iorio FPL(05);
Abramowicz et al PRA(07)
[on the photon sphere]; Field a0806;
Abramowicz & Bajtlik a0905 [version in which the accelerated twin is older].
Accelerated Observers > s.a. Acceleration:
Jerk; modified
electrodynamics; rotations.
@ General references: Desloge & Philpott AJP(87)mar;
Desloge AJP(89)jul
[spatial geometry]; Tartaglia & Ruggiero EJP(03)gq;
Mashhoon gq/03-in,
IJMPD(05)gq/03-in
[non-locality]; Pardy gq/03;
Alba & Lusanna
gq/03 [3+1
view].
@ Rotation, rotating frames: Weber AJP(97)jun
[disk]; Tartaglia FP-phy/98
[Ehrenfest
paradox];
Herrera NCB(00)gq/99;
Bashkov & Malakhaltsev gq/00, gq/01;
Klauber gq/01 [frequency
and wavelength of light]; Rodrigues & Sharif FP(01)
[and
Sagnac
effect];
Rizzi & Ruggiero
FP(02),
03; Peres gq/04/AJP;
Klauber FP(07)gq/06;
Herrera
mp/06 [and
Thomas precession]; > s.a. Sagnac
Effect; time.
@ Related topics: Gruber & Price AJP(97)oct
[t dilation]; Chicone & Mashhoon
CQG(04)gq [critical
speed c/21/2].
Related Topics > s.a. classical
particles [relativistic]; physics
teaching.
@ Lorentz "rotations": Terrell PR(59);
Weisskopf PT(60)sep;
in
Taylor & Wheeler 92, 92-93;
@ Simultaneity: Havas GRG(87);
Sarkar & Stachel PhSc(99)jun;
Giulini gq/00;
Mamone FP(01);
Janis in(02);
Scherr et al AJP(02)dec
[student beliefs]; Bolós et
al
IJTP(02)gq/05 [spacelike
vs lightlike]; Minguzzi gq/05-in
[in special and general relativity]; > s.a. EPR
paradox.
@ Velocity: Lévy-Leblond AJP(80)may;
Mermin AJP(83)dec,
90 ch19 [addition];
Sen JMP(90)
[relative velocities]; Mathews AJP(05)jan
[and acceleration].
@ Other topics: Christodoulou & O'Murchadha CMP(81)
[boost problem in general relativity];
Coll & Morales IJTP(92)
[frames]; Mermin
AJP(97)jun, AJP(98)dec
[spacetime diagrams]; Pierceaux phy/04-in
[Poincaré's
kinematics and light fronts]; Price AJP(05)may-gq [projectiles
and pendula]; Dryzek et al AJP(06)jan
[lab experiment on E2 = p2c2 + m2c4].
> Other topics: see
clocks; Gyrogroup; Pythagorean
Theorem; Rapidity; Rigid
Body; Superluminal Motion; tachyons.
main page – abbreviations – journals – comments – other
sites – acknowledgements
send feedback and suggestions to bombelli at olemiss.edu – modified 1
nov
2009